This invention relates generally to gas turbine engines, and more particularly, to methods and apparatus for cooling gas turbine engine components.
Within known gas turbine engines, combustor and turbine components are directly exposed to hot combustion gases. As such, the components are cooled during operation by pressurized air channeled from the compressor. However, diverting air from the combustion process may decrease the overall efficiency of the engine.
To facilitate cooling engine components while minimizing the adverse effects to engine efficiency, at least some engine components include dedicated cooling channels coupled in flow communication with cooling lines. In at least some known engines, the cooling channels may include cooling holes through which the cooling air is re-introduced into the combustion gas flowpath. Film cooling holes are common in engine components and provide film cooling to an external surface of the components and facilitate internal convection cooling of the walls of the component. To facilitate protecting the components from the hot combustion gases, the exposed surfaces of the engine components may be coated with a bond coat and a thermal barrier coating (TBC) which provides thermal insulation.
The durability of known TBC may be affected by the operational temperature of the underlying component to which it is applied. Specifically, as the bond coating is exposed to elevated temperatures, it may degrade, and degradation of the bond coating may weaken the TBC/bond coating interface and shorten the useful life of the component. However, the ability to cool both the bond coating and/or the TBC is limited by the cooling configurations used with the component.